Such a hydraulic steering is, for example, known from DE 10 2006 010 695 A1. A vehicle equipped with such a steering can either be steered via the steering unit, the driver then usually activating a steering member, for example a steering handwheel, or via the steering valve. When the driver steers the vehicle by means of the steering unit, in many cases a so-called reaction behaviour is desired, that is, the driver must feel through the steering handwheel that forces are acting upon the steering motor. However, this reaction behaviour causes problems, if the vehicle is steered by means of the steering valve. Thus, in the state of the art a reaction suppression arrangement has been proposed, in which a valve is arranged in one or both pipes between the steering unit and the steering motor, said valve(s) being able to interrupt or release the pipe(s).
In some cases, it happens that a valve gets stuck, that is, in spite of an activation signal the valve does not change its position as specified by the activation signal. In the state of the art this causes problems, if a valve of the reaction suppression arrangement gets stuck. In this case, the pipe between the steering unit and the steering motor is blocked, so that the driver can no longer steer the vehicle via the steering unit.